CN113073003A

CN113073003A - Extraction method of avocado oil

Info

Publication number: CN113073003A
Application number: CN202110347522.9A
Authority: CN
Inventors: 欧阳红军; 李普旺; 刘义军; 陈晶晶; 李国�; 徐志军
Original assignee: South Subtropical Crops Research Institute CATAS
Current assignee: South Subtropical Crops Research Institute CATAS
Priority date: 2021-03-31
Filing date: 2021-03-31
Publication date: 2021-07-06

Abstract

The invention discloses an extraction method of avocado oil, which comprises the following steps: (1) pretreatment: comprises cleaning, ripening, peeling and removing core; (2) pulping: pulping the pulp, controlling the pulping temperature and the pulping time, and heating for a certain time to obtain coarse pulp; (3) grinding: adding a proper amount of water and sodium chloride into the coarse fruit pulp, uniformly stirring, and then grinding the mixture by using a colloid mill to obtain fruit pulp; (4) demulsification treatment: adjusting the pH value of the pulp, then adding enzyme, adjusting the temperature of the pulp, and stirring and reacting in a nitrogen-filled stirring tank; (5) vacuum boiling demulsification: adding a proper amount of ethanol into the fruit pulp subjected to enzymolysis, heating, and vacuumizing to realize demulsification of the fruit pulp; (6) three-phase separation: transferring the demulsified pulp into a separator, collecting an oil phase, filling nitrogen for protection, and cooling; (7) centrifuging to remove impurities: and (4) transferring the oil phase into a centrifugal machine for treatment, removing colloid precipitates, and collecting the oil phase to obtain the avocado oil. The method provided by the invention adopts low-temperature extraction, the process is simple and convenient, the nutritional quality and flavor of the avocado are more completely maintained, and the extracted avocado oil is rich and diverse in components and high in purity.

Description

Extraction method of avocado oil

Technical Field

The invention relates to the technical field of avocado processing, and particularly relates to a method for extracting avocado oil.

Background

The avocado oil is high-grade edible oil for human consumption, is vegetable oil obtained by finely pressing and purifying tropical fruit avocados serving as main raw materials, is dark green in color and rich in beef tallow taste, can be used for cooking various foods, can be used as cold vegetable dish or salad, can be directly eaten, and can relax bowel, clear bowels and expel toxin. It is well known that shea butter is also a super moisturizer and emollient that has anti-inflammatory properties and is effective in treating skin problems such as allergies, burns, rashes and eczema. It is widely used in the cosmetics and food industries due to its specific efficacy.

The avocado is processed by extracting with solvent, hot pressing, refining, bleaching, and deodorizing to obtain refined oil. The invention discloses an enzymatic extraction method of avocado oil, which comprises the following steps: pulping, inactivating enzyme, adjusting pulp concentration, performing enzymolysis, and separating oil, water and residue. The temperature of the materials in the whole processing process of the method does not exceed 80 ℃, so bitter substances are not generated, and the obtained avocado oil has less impurities, low acid value and good color. The method adopts an enzymolysis method to destroy the pulp cell structure, separates out oil as much as possible, has obvious effect, greatly improves the oil yield, and has the highest extraction rate of the oil pear oil reaching 94.26 percent (CN201510872844. X). The method researches the influence of different solvent types, material-liquid ratios, ultrasonic extraction time, ultrasonic temperature, ultrasonic power and the like on the extraction effect of the avocado oil in a patent experiment, and determines that the process for extracting the avocado oil by ultrasonic assistance comprises the following steps: the material-liquid ratio is 1: 35g/mL, the extraction time is 35min, the ultrasonic power is 300W, and the extraction temperature is 25 ℃. Under the condition, the extraction rate of the avocado oil is 64.7 percent (thesis: the process for extracting the avocado oil by ultrasonic wave assistance). Jinzhongen and the like invent a method for extracting unsaturated fatty acid from avocado, the extraction method is simple to operate, and the purity of the extracted unsaturated fatty acid is high (CN20151063975. X). The plum-loving surface method optimizes the process for extracting the avocado oil by the water-substitution method, and the optimal process conditions for extracting the avocado oil by the water-substitution method are determined as follows: the pH value is 4.69, the water bath temperature is 100 ℃, the water bath time is 0.5h, the water-material ratio is 4.35, and the extraction rate of the avocado oil under the condition is 85.97 percent. The removal capacity of hydroxyl free radicals and superoxide anions of the avocado oil proposed under the condition is stronger than that of ascorbic acid, and the reduction capacity is weaker than that of the ascorbic acid (a paper is that the response surface optimizes the avocado oil extraction process and the inoxidizability research thereof). The best extraction process for extracting the avocado oil by an aqueous method is researched by the panda and the like, and the best extraction process is determined as follows: the ratio of material to water is 1: 6g/mL, the extraction time is 3h, the extraction temperature is 25 ℃, the centrifugal speed is 4400r/min, and the oil yield can reach 72.86 percent under the condition. The avocado oil obtained by the aqueous solution method is light yellow green, transparent and has avocado fragrance. The acid value and the peroxide value of the water aqua method extracted oil both meet the quality standard of the national edible oil. Fatty acid analysis is carried out on the avocado oil extracted by the aqueous method, and 19 fatty acid components, mainly unsaturated fatty acids, are detected. Wherein 9C 18:1, 11C 18:1, 9C12C 18: 2n-6, C16:0, and 9C 16: 1 are the main fatty acids of the avocado oil (thesis: the avocado oil extracted by aqueous solution method and the research on its physicochemical properties). Welin and the like research main influence factors of the centrifugal separation method for extracting the avocado oil, has simple technology, high efficiency and practicability, and can be used for industrial production (thesis: the process research of the centrifugal separation method for extracting the avocado oil). And K.H. Southwell, etc. by using a small-sized screw press, the black avocado oil is pressed from the avocados which are dried, denucleated, peeled or peeled. The yield of the crude oil of the avocado is high, and the oil yield reaches 79.4-90.3%. The natural clear crude pear oil is neutralized and bleached by various kinds of diatomite to obtain light yellow or medium yellow oil. The oil pear oil is rich in oleic acid (67.9-72.2%), and the components are similar to olive oil (thesis: extraction and refining of oil pear oil). Because the avocado oil has very strong hydrophilicity and is very easy to emulsify, the avocado contents with different maturity degrees are different, the oil components are different, and the extraction process parameters have larger difference, the method does not solve the problem well. Based on the method, on the basis of the traditional method, a plurality of improvements are made, a novel method for extracting the avocado oil is invented, the ripening technology is adopted to control the ripening of the avocado, and the content and the quality of the avocado oil are improved; the enzymolysis technology is adopted to destroy the structures of pulp, protein and the like in the pulp, and the dissolution rate of the avocado oil is promoted; the alcohol adding vacuum low-temperature demulsification technology is adopted to reduce the oil-water emulsification degree and promote oil-water separation; low-temperature precipitation and high-speed centrifugation are adopted to remove impurities, wax and other components in the grease are removed deeply, and the storage stability of the grease is better.

Disclosure of Invention

The invention aims to overcome the defects in the prior art, and provides a novel method for extracting the avocado oil, wherein ripening technology is adopted to control the ripening of the avocado, so that the content and the quality of the avocado oil are improved; the enzymolysis technology is adopted to destroy the structures of pulp, protein and the like in the pulp, and the dissolution rate of the avocado oil is promoted; the alcohol adding vacuum low-temperature demulsification technology is adopted to reduce the oil-water emulsification degree and promote oil-water separation; low-temperature precipitation and high-speed centrifugation are adopted to remove impurities, wax and other components in the grease are removed deeply, and the storage stability of the grease is better.

In order to achieve the purpose, the invention provides an extraction method of avocado oil, which comprises the following steps:

(1) pretreatment: comprises cleaning, ripening, peeling and removing kernels.

(2) Pulping: adding a certain material-water ratio into the pulp for pulping, controlling a certain pulping temperature and pulping time, then heating the pulp to a certain temperature, and maintaining for a certain time to obtain the coarse pulp.

(3) Grinding: adding appropriate amount of water and a certain proportion of sodium chloride into the coarse fruit pulp, stirring uniformly, and then adopting a colloid mill to carry out pulp grinding to obtain the fruit pulp.

(4) And (3) enzymolysis treatment: adding sodium hydroxide or hydrochloric acid with a certain concentration to adjust the pH value of the pulp, then adding a certain amount of enzyme, adjusting the temperature of the pulp, and stirring while carrying out enzymolysis in a nitrogen-filled stirring tank.

(5) Vacuum boiling demulsification: adding a proper amount of ethanol into the fruit pulp after enzymolysis, heating and vacuumizing to realize demulsification of the fruit pulp.

(6) Three-phase separation: transferring the demulsified pulp into a separator to realize oil-water-solid three-phase separation, collecting an oil phase, filling nitrogen for protection, and cooling for a certain time.

(7) Centrifuging to remove impurities: transferring the oil phase into a centrifuge, removing colloid precipitate, and collecting the oil phase to obtain avocado oil.

Preferably, the cleaning method in the step (1) is to place fresh and mildew-free avocado into a high-pressure ozone cleaning pool for cleaning for 1-5min after the stem of the avocado is removed, the ozone concentration is controlled to be 1.0-4.0mg/L, and the cleaning water temperature is 20-30 ℃.

Preferably, the ripening method in the step (1) is to put the washed avocado into a closed environment with the temperature of 25-35 ℃ and the humidity of 60-85% to ripen, the color of the pericarp is changed from dark green to brown, and the ripening is finished.

Preferably, the ratio of pulping material to water in the step (2) is 1:2-1:6, the pulping temperature is 20-30 ℃, the heating temperature after pulping is 40-60 ℃, and the heating time is 0.5-2 min.

Preferably, the ratio of the refining material to water in the step (3) is 1:2-1:7, the addition of sodium chloride is 1-8%, and the gap of the colloid mill is 10-40 μm.

Preferably, the concentration of sodium hydroxide or hydrochloric acid in the step (4) is 0.1 mol/L; the enzyme is one or more of alkaline protease, acid protease and pectinase, the addition amount of the enzyme is 1-8 per mill, the enzymolysis time is 0.5-3h, and the enzymolysis temperature is 35-75 ℃.

Preferably, the concentration of the ethanol in the slurry in the step (5) is 5-50%, the heating temperature is 50-65 ℃, and the vacuum degree is-0.08 to-0.1 MPa.

Preferably, the separator in the step (6) is a three-foot butterfly separator, and the stirring rotation speed is set to be 5000-; and collecting an oil phase after the completion, wherein the cooling temperature of the oil phase is 4-15 ℃, and the cooling time is 1-30 days.

Preferably, the centrifuge in the step (7) is a GF type tubular centrifuge, and the rotation speed is set to 15000-.

Compared with the prior art, the invention has the beneficial effects that:

(1) ripening technology is adopted to control the ripening of the avocado, so that the avocado oil has high content and good quality;

(2) the enzymolysis technology is adopted to destroy the structures of pulp, protein and the like in the pulp, and the dissolution rate of the avocado oil is promoted; the alcohol adding vacuum low-temperature demulsification technology is adopted to reduce the oil-water emulsification degree and promote oil-water separation; low-temperature precipitation and high-speed centrifugation are adopted to remove impurities, wax and other components in the grease are removed deeply, and the storage stability of the grease is better.

(3) In the method, a nitrogen-filled type stirring tank is adopted in the stirring process, so that air in the fruit pulp and on the surface of the fruit pulp is replaced, the oxidation reaction of the oil in the extraction process is effectively reduced, and the edible quality of the oil is improved;

(4) the method adopts low-temperature extraction method, the temperature of the whole extraction process is lower than 75 ℃, the loss of bioactive components such as 2,2' -methylene bis- (4-methyl-6-tert-butylphenol) and the like in the oil refining process is avoided, the generation of non-effective components is reduced, and the nutritional quality and flavor of avocado are maintained.

Drawings

FIG. 1 is a gas chromatogram of an embodiment of the invention;

FIG. 2 is a gas chromatogram of comparative example 1 according to the present invention;

FIG. 3 is a gas chromatogram of comparative example 2 according to the present invention;

FIG. 4 is a gas chromatogram of comparative example 3 according to the present invention.

Detailed Description

The following further describes a specific embodiment of the present invention with specific examples, which are intended to describe the technical solution in detail, but not to limit the technical solution. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

The embodiment provides an extraction method of avocado oil, which comprises the following steps:

(1) selecting fresh and mildew-free avocados, removing stems, cleaning in a high-pressure ozone cleaning pool for 3min, wherein the ozone concentration is 1.5mg/L, the cleaning water temperature is 25 ℃, cleaning, placing the avocados in a closed environment with the temperature of 25 ℃ and the humidity of 75% for ripening, until the color of the peel is changed from dark green to brown, and manually peeling and removing kernels;

(2) placing pulp in water of 40 deg.C for 1min, adding 3 times of water, heating to 25 deg.C, pulping for 20s, filtering with 40 mesh screen, heating the filtrate to 45 deg.C, maintaining for 1min to realize enzyme passivation to obtain coarse pulp;

(3) re-pulping, adding 2 times of water according to the weight of the original pulp, heating to 25 deg.C, adding 2% sodium chloride, stirring, and grinding in colloid mill to obtain pulp with particle size of about 15 μm;

(4) adjusting pH of the pulp to about 6.0, adding 2 ‰ acid protease for enzymolysis, transferring the pulp into nitrogen-filled sealed stirring tank, stirring, controlling temperature at 50 deg.C, and stirring for 2 hr;

(5) vacuum boiling demulsification: adding ethanol into the fruit pulp after enzymolysis, wherein the ethanol concentration of the pulp is 5%, the heating temperature is 55 ℃, vacuumizing, and the vacuum degree is-0.08 Mpa, so as to realize demulsification of the fruit pulp;

(6) transferring the stirred fruit pulp into a three-foot disc separator for solid-liquid three-phase separation, setting the rotating speed to be 6525r/min, collecting an oil phase after the separation, cooling the oil phase collection to 10 +/-1 ℃, and standing for 30 days;

(7) transferring the collected oil phase into a GF75 tubular centrifuge, setting the rotation speed at 18000r/min, removing colloid precipitate, collecting oil phase to obtain avocado oil, and packaging the avocado oil.

Example 2

(1) selecting fresh and mildew-free avocados, removing stems, cleaning in a high-pressure ozone cleaning pool for 1min, wherein the ozone concentration is 2.0mg/L, the cleaning water temperature is 25 ℃, cleaning, placing the avocados in a closed environment with the temperature of 25 ℃ and the humidity of 70% for ripening until the color of the peel is changed from dark green to brown, manually peeling and removing kernels, and taking pulp;

(2) placing the pulp in water of 45 deg.C for 2min, adding 3 times of water at 25 deg.C, pulping for 15s, filtering with 40 mesh screen, heating the filtrate to 50 deg.C, and maintaining for 1min to realize enzyme passivation;

(3) re-pulping, adding 2.5 times of water according to the weight of the original pulp, heating to 25 deg.C, adding 3% sodium chloride, stirring, and grinding in colloid mill to obtain pulp with granularity of about 25 μm;

(4) adjusting pH of the pulp to about 7.5, adding 2 ‰ alkaline protease for enzymolysis, transferring the pulp into nitrogen-filled sealed stirring tank, stirring, controlling temperature at 50 deg.C, and stirring for 2 hr;

(5) vacuum boiling demulsification: adding ethanol into the fruit pulp after enzymolysis, wherein the ethanol concentration of the pulp is 50%, the heating temperature is 65 ℃, vacuumizing, and the vacuum degree is-0.1 Mpa, so as to realize demulsification of the fruit pulp;

(6) transferring the stirred fruit pulp into a disc separator for solid-liquid three-phase separation, setting the rotating speed to be 6520r/min, collecting an oil phase after the separation is finished, cooling the collected oil phase to 10 +/-1 ℃, and standing for 30 days;

(7) transferring the collected oil phase into a GF75 tubular centrifuge, setting the rotating speed at 17000r/min, centrifuging, collecting the oil phase to obtain the avocado oil, and packaging the avocado oil.

Example 3

(1) selecting fresh and mildew-free avocados, removing stems, cleaning in a high-pressure ozone cleaning pool for 3min, wherein the ozone concentration is 1.0mg/L, the cleaning water temperature is 25 ℃, cleaning, placing the avocados in a closed environment with the temperature of 25 ℃ and the humidity of 75% for ripening, manually peeling and removing kernels until the color of the peel is changed from dark green to brown, and taking pulp;

(2) placing pulp in water of 40 deg.C for 1min, adding 3 times of water, heating to 25 deg.C, pulping for 20s, filtering with 40 mesh screen, heating to 50 deg.C, and maintaining for 1min to realize enzyme passivation;

(3) re-pulping, adding 2 times of water according to the weight of the original pulp, heating to 25 deg.C, adding 2.5% sodium chloride, stirring, and grinding in colloid mill to obtain pulp with granularity of about 15 μm;

(4) adjusting the pH value of the fruit pulp to about 6.5, adding 2 per mill of acid protease for enzymolysis, transferring the fruit pulp into a nitrogen-filled sealed stirring tank, stirring, controlling the temperature to be 55 ℃, and stirring for 2 hours;

(5) vacuum boiling demulsification: adding ethanol into the fruit pulp after enzymolysis, wherein the ethanol concentration of the pulp is 10%, the heating temperature is 60 ℃, vacuumizing, and the vacuum degree is-0.01 Mpa, so as to realize demulsification of the fruit pulp;

(6) transferring the stirred fruit pulp into a disc separator for solid-liquid three-phase separation, setting the rotating speed to be 6550r/min, collecting an oil phase after the separation is finished, cooling the oil phase collection to 10 +/-1 ℃, and standing for 30 days;

(7) transferring the collected oil phase into a GF75 tubular centrifuge, setting the rotating speed at 19000r/min, centrifuging, collecting the oil phase to obtain the avocado oil, and packaging the avocado oil.

Example 4

(1) selecting fresh and mildew-free avocados, removing stems, cleaning in a high-pressure ozone cleaning pool for 2min, wherein the ozone concentration is 2.0mg/L, the cleaning water temperature is 25 ℃, cleaning, placing the avocados in a closed environment with the temperature of 25 ℃ and the humidity of 75% for ripening, manually peeling and removing kernels until the color of the peel is changed from dark green to brown, and taking pulp;

(2) placing pulp in water of 40 deg.C for 1min, adding 3 times of water at 25 deg.C, pulping for 15s, filtering with 40 mesh screen, heating the filtrate to 45 deg.C, and maintaining for 1min to realize enzyme passivation;

(3) re-pulping, adding 2 times of water according to the weight of the original pulp, heating to 25 deg.C, adding 2% sodium chloride, stirring, and grinding in colloid mill to obtain pulp with granularity of about 25 μm;

(4) adjusting pH of the pulp to about 7.8, adding 2 ‰ alkaline protease for enzymolysis, transferring the pulp into nitrogen-filled sealed stirring tank, stirring, controlling temperature at 50 deg.C, and stirring for 2 hr;

(6) transferring the stirred fruit pulp into a disc separator for solid-liquid three-phase separation, setting the rotating speed to be 6500r/min, collecting an oil phase after the separation is finished, cooling the collected oil phase to 10 +/-1 ℃, and standing for 30 days;

(7) transferring the collected oil phase into a GF75 tubular centrifuge, setting the rotating speed at 16000r/min, centrifuging, collecting the oil phase to obtain avocado oil, and packaging the avocado oil.

Comparative example 1

Extracting the avocado oil from the avocado by adopting a hot pressing method in the prior art.

Comparative example 2

Extracting avocado oil from avocado by extraction method in the prior art, and using ethanol as solvent.

Comparative example 3

Extracting avocado oil from avocado by adopting an extraction method in the prior art, and taking n-hexane as a solvent.

In order to prove the effect of the invention, fatty acid component detection analysis is carried out on the avocado oil sample extracted by the method provided by the invention and the avocado oil samples obtained in comparative examples 1-3, and the obtained results are shown in Table 1:

table 1 fatty acid composition and amount in sample

As can be seen from Table 1, the preparation method of the present invention is superior to comparative examples 1 to 3, which are specifically shown in the following:

(1) the avocado oil prepared by the method has high yield which is more than 15 percent, and the extracted oil has rich and various components and contains palmitic acid, oleic acid, linoleic acid, arachidic acid, 2' -methylene bis- (4-methyl-6-tert-butylphenol) and squalene. Wherein the content of C16:0 is more than 11%, the content of C18:1 is more than 70%, the content of C18:2 is more than 10%, the content of C20:0 is more than 0.1%, the content of 2,2' -methylene bis- (4-methyl-6-tert-butylphenol) is more than 0.02%, and the content of squalene is more than 0.1%.

(2) The oils extracted in comparative examples 1, 2 and 3 did not contain arachidic acid, 2' -methylenebis- (4-methyl-6-tert-butylphenol) and squalene. Comparative example 3 the sample obtained by the extraction method does not contain 2,2' -methylene bis- (4-methyl-6-tert-butylphenol), and the component is a natural oil antioxidant which can improve the stability of the avocado oil;

(3) the avocado oil prepared by the extraction method has higher oleic acid content and squalene content than comparative example 1, comparative example 2 and comparative example 3.

In addition, as can be seen from the gas chromatograms in fig. 1 to fig. 4, the impurity peaks of the shea butter of the present invention are fewer, which indicates that the shea butter obtained by the extraction method of the present invention has fewer impurities, higher purity and better quality.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. The extraction method of avocado oil is characterized by comprising the following steps:

(1) pretreatment: comprises cleaning, ripening, peeling and removing kernels.

2. The method for extracting avocado oil according to claim 1, wherein the cleaning method in step (1) is to remove the stem of fresh and mildew-free avocado, then place the fresh and mildew-free avocado in a high-pressure ozone cleaning pool for cleaning for 1-5min, wherein the ozone concentration is controlled to be 1.0-4.0mg/L, and the cleaning water temperature is 20-30 ℃.

3. The method for extracting avocado oil according to claim 1, wherein the ripening method in the step (1) is to put the cleaned avocado in a closed environment with a temperature of 25-35 ℃ and a humidity of 60-85% for ripening, the color of the peel is changed from dark green to brown, and the ripening is finished.

4. The extraction method of avocado oil according to claim 1, wherein in the step (2), the ratio of pulping material to water is 1:2-1:6, the pulping temperature is 20-30 ℃, the heating temperature after pulping is 40-60 ℃, and the heating time is 0.5-2 min.

5. The method for extracting avocado oil according to claim 1, wherein the ratio of refining material to water in step (3) is 1:2-1:7, the addition amount of sodium chloride is 1-8%, and the gap between colloid mills is 10-40 μm.

6. The extraction method of shea butter of claim 1, wherein the concentration of sodium hydroxide or hydrochloric acid in step (4) is 0.1 mol/L; the enzyme is one or more of alkaline protease, acid protease and pectinase, the addition amount of the enzyme is 1-8 per mill, the enzymolysis time is 0.5-3h, and the enzymolysis temperature is 35-75 ℃.

7. The method for extracting avocado oil according to claim 1, wherein the concentration of the serous fluid ethanol in the step (5) is 5-50%, the heating temperature is 50-65 ℃, and the vacuum degree is-0.08 to-0.1 MPa.

8. The method for extracting avocado oil according to claim 1, wherein the separator in step (6) is a three-legged butterfly separator, and the stirring speed is set to 5000-; and collecting an oil phase after the completion, wherein the cooling temperature of the oil phase is 4-15 ℃, and the cooling time is 1-30 days.

9. The method for extracting shea butter as recited in claim 1, wherein the centrifuge in step (7) is a GF type tubular centrifuge, and the rotation speed is 15000-.